The present disclosure relates to a driving circuit board mounted with, for example, a top gate thin film transistor (TFT) and a pixel electrode, and a method of manufacturing the driving circuit board, as well as a display unit and an electronic apparatus that have the driving circuit board.
In recent years, a TFT using an organic semiconductor as a channel has been developed. A method of manufacturing a TFT using an inorganic semiconductor as a channel is diverted to a method of manufacturing the TFT using the organic semiconductor as the channel. Specifically, a semiconductor layer is formed using a vacuum evaporator or a sputtering apparatus. However, the facility cost thereof is high when these apparatuses are used, and thus a manufacturing method that is less in equipment investment, is simplified, and covers a large area has been developed. As an example, a technology of forming a channel layer by an applying and printing system has been developed by making use of soluble property of the organic semiconductor. The applying and printing system is applicable not only to formation of the semiconductor layer, but also to formation of an insulating layer and wirings that configure the TFT, and is considered to be differentiated from an inorganic TFT in cost.
In addition, the organic semiconductor is gradually improved in basic property such as mobility as compared with that of the inorganic semiconductor, and it is reported that the organic semiconductor has property equivalent to or more than the property of an amorphous silicon depending on materials. In this way, it is considered that the TFT become more common than ever before as the organic TFT using the organic semiconductor with high performance is decreased in cost. For example, it is possible to allow books, newspapers, magazines that currently mainly cope with still images, to cope with moving images with the same price. Moreover, it is possible to achieve a situation where a still image display body that is disposable or is assumed to be kept for a short period, such as an admission ticket and other tickets is allowed to display moving images. As described, to allow the display body capable of performing moving display to become common to the society, it is necessary to further suppress the price of the TFT controlling the display body.
To suppress the price of the organic TFT, it is conceivable that cost reduction of use materials, improvement in material usage efficiency, simplification of the TFT structure, and reduction of manufacturing steps by simplification are effective, in addition to use of an applying and printing method with lower cost as a method of forming the channel layer, as described above. Here, as the structure of the organic TFT now under development, a bottom gate (inverted staggered) structure as illustrated in, for example, PTL 1 is mainstream.